Crop Factor Calculator
Crop factor is the diagonal of a full frame sensor (43.27 mm) divided by the diagonal of yours. It tells you what focal length and aperture give the same picture on full frame. Enter your sensor and lens below.
Your camera and lens
Result
How the crop factor is calculated
Short answer: crop factor = 43.27 mm ÷ your sensor diagonal. A Canon APS-C body is 1.61×, a Nikon or Sony APS-C body 1.53×, Micro Four Thirds 2.0× and Fujifilm GFX 0.79×. Multiply the focal length by the crop factor to get the full frame equivalent, and do the same to the f-number to compare depth of field.
The diagonal of a 36 × 24 mm frame is √(36² + 24²) = 43.27 mm. Dividing that by your sensor's diagonal gives a single number that converts every lens you own into full frame terms:
- Focal length: 50 mm on a 1.5× body frames like 75 mm on full frame. The lens does not change; the sensor simply records a narrower part of the image circle.
- Aperture: multiply as well. An f/2 lens on Micro Four Thirds matches the depth of field of f/4 on full frame, and gathers the same total light as f/4 spread over a quarter of the area. Exposure per unit area is unchanged, which is why your meter still reads f/2.
- ISO: do not multiply. ISO is a per-area sensitivity; the smaller sensor simply has less area, which is why its low light performance is worse by roughly the same factor.
Crop factor by sensor size
| Sensor | Dimensions (mm) | Diagonal | Crop factor | Matches 50 mm with | Matches f/2.8 with |
|---|---|---|---|---|---|
| Full frame | 36 × 24 | 43.27 | 1.00× | 50 mm | f/2.8 |
| APS-C (Nikon, Sony, Fuji) | 23.5 × 15.6 | 28.21 | 1.53× | 32.6 mm | f/1.8 |
| APS-C (Canon) | 22.3 × 14.9 | 26.82 | 1.61× | 31.0 mm | f/1.7 |
| Micro Four Thirds | 17.3 × 13.0 | 21.64 | 2.00× | 25.0 mm | f/1.4 |
| 1 inch | 13.2 × 8.8 | 15.86 | 2.73× | 18.3 mm | f/1.0 |
| 1/1.7 inch | 7.6 × 5.7 | 9.50 | 4.55× | 11.0 mm | f/0.6 |
| 1/2.3 inch | 6.17 × 4.55 | 7.67 | 5.64× | 8.9 mm | f/0.5 |
| Fujifilm GFX | 43.8 × 32.9 | 54.78 | 0.79× | 63.3 mm | f/3.5 |
| Phase One IQ4 | 53.4 × 40.0 | 66.72 | 0.65× | 77.1 mm | f/4.3 |
Common questions
Does crop factor change depth of field?
Yes, if you frame the subject the same way. To match the framing you either move back or use a shorter lens, and both increase depth of field. The full frame camera at f/2.8 therefore separates the subject more than a 2× sensor at f/2.8. Multiply the f-number by the crop factor to compare the two fairly: f/2.8 on Micro Four Thirds equals f/5.6 on full frame.
Is crop factor the same as zoom?
No. Crop factor describes how much of the image circle the sensor records. A 1.5× sensor records a smaller area, so the picture looks like a longer lens was used, but the lens magnification and the perspective are unchanged. Nothing is optically zoomed.
Does crop factor change exposure?
No. f/2 at 1/100 s and ISO 100 gives the same brightness on any sensor size. Only the total light collected and the depth of field change, because the sensor area changes.